Years back a non UK/EU citizen could just rock up to the UK border clutching a faxed/emailed letter of invitation from a well known UK offshore operating company (more often than not Aberdeen based) and they let you in as you were going to work outside the 12 mile limit….Technically international waters, until it comes to paying income tax that is!
South African divers and others used to do this all the time.
My feeling is this has changed somewhat. Anyone got any facts on the topic?
I know in Canada to get offshore, unless you are a Canadian national or Permanent resident you need a work permit to work offshore. Immigration Canada don’t give them away too easily I can tell you!